Concentration of sylvinite ores



Patented June 29, 1943 CONCENTRATION OF SYLVINITE ORES Allen T. Cole andJames B. Duke, Mulberry, and Karl F. Schilling, Lakeland, Fla.,assignors, by mesne assignments, to Minerals Separation North AmericanCorporation, New York, N. Y., a corporation of Maryland No Drawing.Application June 2, 1942, Serial N0. 445,450

, 14 Claims. (01. 209166) This invention relates to the concentrating,or separation of the values from soluble ores. More particularly, itrelates to the separation of sylvite (potassium chloride-K01) from asaturated solution of the soluble constituents of sylvinite ores such,for example, as those found in the Carlsbad district of New Mexico.

The invention resides in improved methods of effecting the separation ofthe desired sylvite from such ores by froth flotation, skin flotation,agglomeration tabling and other methods involving wet stratificationwith the use of appropriate agents which effect the separation of thesylvite from the other ore constituents.

It is already known that sylvite can be recovered from a saturatedsolution of the soluble constituents of sylvinite ore in accordance withwell-established concentration operations by using as a collector analiphatic amine containing a straight chain hydrocarbon group of atleast 7 carbon atoms, or the salts of such amines resulting from theircombination with water-soluble acids.

The general objects of the present invention are to produce concentratesof the desired sylvite which are of high commercial grade, with highpercentages of recovery, with economy in the use of reagents and withreliable and easily controlled operation of the plant. These objects areattained by the processes embodying the present invention which arehereinafter described.

The methods of the present invention are the result of the discoverythat greatly improved results, as to grade and recovery of the desiredsylvite and as to control of operations, can be obtained by the use, inconjunction with the aforesaid straight chain alkyl amines used ascollectors, of dextrin as an auxiliary agent.

The straight chain alkyl amines useful as 001- lectors for sylvite, theaction of which is improved by the concurrent use of dextrin as anauxiliary agent, include the following aliphatic primary amines:n-heptylamine, n-octylamine, n-nonylamine, n-decylamine, n-undecylamine,n-dodecyiamine, n-tetradecylamine, n-hexadecylamine, n-heptadecylamine,n-octadecylamine, and noctadecenylamine. The lower members of thisseries may be added to the ore pulp in the form of the free base or asthe salts formed by their combination with acids which are themselvesrelatively devoid of surface active properties, such, for example, ashydrochloric acid, nitric acid, acetic acid, etc. The higher members ofthe series, being much less soluble, are generally used in the form oftheir more soluble salts.

These amine collectors may be used individually or as mixtures, Themixtures need not necestheir salts but may also contain varyingproportions of aliphatic secondary and tertiary amines or their salts,such as are commonly found in commercial products. For example, theproduct of Armour and Company sold under the designation Am.Ac.118DC isvery suitable and is understood to consist of approximately 73%monooctadecylamine acetate, about 24% mono-hexadecylamine acetate,together with small quantities of secondary and tertiary amine acetates.Another suitable commercial product is that sold by E. I du Pont,de'Nemours & Company, Inc., as D. P. 243" which is a 50% aqueous pasteof technical laurylamine hydrochloride understood to containapproximately 18% octylamine hydrochloride, 10% decylamine.hydrochloride, 55% laurylamine hydrochloride, 17% myristylaminehydrochloride, and traces of secondary and tertiary amines.

.The term dextrin is employed herein and in the claims as indicating thepartial degradation and/or hydrolytic products of starch. It may beprepared from potato, corn, cassava, tapioca, rice, or wheat starch byheating it alone or in the presence of a catalyst, by heating an aqueousstarch suspension with an acid or by conversion with enzymes. Excellentresults have been obtained with either the white or yellow dextrins ofcommerce, made from corn and potato starches respectively. The dextrinsare preferably used in the form of aqueous solutions or suspensions.

In practicing the methods of the present invention, desliming of thesylvinite ore is desirable; and it is also sometimes desirable to add afrothing agent, such as pine oil, in addition to the collector and thedextrin, when the desired mineral is to be concentrated by frothflotation, or a petroleum oil such as fuel oil when concentration iseffected by tabling.

The following contrasting examples giving the results obtained inconcentrating sylvite, without and with the use of dextrin as anauxiliary agent in conjunction with a straight chain alkyl aminecollector, illustrate the advantages obtained "by employing the methodsof the present invention; but the invention is not to be construed asbeing limited to the details hereinafter described.

EXAMPLE I.--No ,dextrin.Sylvinite ore from Carlsbad, New Mexico,wascrushed so that it would pass through a IO-mesh screen, and was madeinto a pulp of about 20% solids with a saturated solution of oreconstituents. Reagents, as hereinafter specified, were added to thispulp, the pulp was agitated about 10 seconds to distribute the reagentsand flotation was then eflected. The first or rougher froth concentratewas returned to the flotation machine, diluted and refloated. This wasrepeated on the second froth concentrate. The reject of the firstflotation operation was final tailings. Rejects of the second and thirdflotation operations were middlings to be returned to the flotationcircuit and further values recovered therefrom. The reagents used weren-heptylamine acetate (introduced as a aqueous solution) 1.00 lb., andpine oil 0.2 lb., both to the ton of ore treated. Results were asfollows:

EXAMPLE II.-With yellow dextrin-This operation was identical withExample 1, except that dextrin was employed as an auxiliary agent. 0.8lb. per ton of yellow dextrin was added to the pulp in the form of a 5%aqueous solution, in addition to the reagents used in Example I. Theresults were as follows:

Product Weight K01 ggg Per cent Per cent Feed 100. 0 30. 6 100.0 1 26.884.6 74. 3 3. e 21. 9 2. o 10. 3 10. 9 3. 7 56.0 9. 3 ,17. o 3. a 22.12. 4

It will be noted that the use of the dextrin in conjunction with theother reagents improved the grade of concentrate by 13.3% (84.6% KClwhen dextrin was used, as against 71.3% KCl Without it) and increasedthe recovery by 31.2% (74.3% as against 43.1%).-

EXAMPLE III.-No dextrin-This test was made on a different sample of ore,also from Carlsbad, and will serve as a basis of comparison for thetests of Examples IV and V. The ore was prepared in the same manner asin Example I and subjected to the same concentrating operations. Thereagents used were the Am.Ac.1180-C described above, a commercial amineacetate product, in the amount of 0.6 lb. and pine all 0.3 lb., both perton of ore. Results were as follows:

K01. Product Weight KCl recovery Per cent Per cent Feed 100. 0 33. 1100.0 Concentrate 17. 0 92. 4 47. 4 Middling 2. 7. 7 86. 0 20. 1Middling i 9. 2 54. 3 15. 3

ailing 62. 6 7. 6 1.4. 4 Slime 3. 6 29. 0 2. 8

EXAMPLE IV.-With white dextrin-The ore, procedure and reagents were thesame as in Example III, except that there was added to the pulp 1.0 lb.per ton of white dextrin in the form of an aqueous solution orsuspension. The results were as follows:

Product Weight KC] gg Per cent Per cent Feed 100. 0 32. 0 100. 0Concentrate 21. 3 97.0 64. 4 Mlddling 2 5. 1 93. 6 14.9 Middling 1. 5. 453. l 8.9 Telling 63.6 4. l 8.4 Slime .Q... 4.6 23.8 3.4

By comparison with Example III it will be seen that the addition of thedextrin increased grade by 4.6% and recovery by 17%.

EXAMPLE V.With yellow. dextrin-The ore, procedure and reagents were thesame as in Example III. except that there was added to the pulp 1.0 lb.per ton of yellow dextrin in the form of an aqueous solution. Theresults were as follows:

KC] Product Weight K01 recovery Percent Percent Feed 100. 0 32. 6 100. 0Concentrate 27. 5 96. 2 81. 5 Middl ng 2 l. 8 82. 4 4. 4 Middhng 1. 3. 530. 3 3. 4 Telling. 62. 8 3. 8 7. 3 Slime 4. 4 23. 9 3. 4

Product recovery EXAMPLE VII.-With yellow dextrin-The ore, procedure andreagent were the same as in Example VI except that 0.8 lb. per ton ofore of yellow dextrin was added as an aqueous solution. Results were asfollows:

KCI Product Weight KCl recovery Percent Percent By comparison ofExamples VI and VII it will be seen that the addition of the dextrinincreased recovery by 27.5% with a very slight drop in grade of 1.9%.

EXAMPLE VIII.--No dextrin-This example and the next illustrate thebeneficial effect of using dextrin as an auxiliary agent in the recoveryof sylvite by table concentration methods. The ore was from the samesource as that used in Examples I and II and was first reduced toparticle sizes ranging from about minus 6 to about plus 35-mesh and thenpartially deslimed. It was then made up to a pulp in which the ratio ofbrine to ore was 1:1.88 by weight and conditioned with the reagent forabout one minute. The sole reagent was "Am.Ac.1180C,' 0.5 lb. per ton ofore. The conditioned pulp was diluted and fed to a shaking table with asaturated aqueous solution of soluble ore constituents. The sylviteconcentrate was recovered at the side of the table and the rejectedconstituents went off at the end of the table. The results were asfollows:

Product Weight KC] recovery cent EXAMPLE IX.With yellow dextrin.-Theore, procedure and reagent were the same as in Example VIII except that0.4 lb. per ton of ore yellow dextrin was added as an aqueous solution.Results were as follows:

x01 Product Weight KCl recovery Percent Percent Feed 100.0 27.3 100.0Concentrate 25. 9 92. 7 87. 9 fiddling 2.5 326 2.9 Middling l... 5. 3 6.5 1. 1 Telling A 65. 5 3. 2 7. 7 Slime 0.8 9.0 0.4

pended claims, the invention may be practiced comprises subjecting saidpulp to a concentrat- 7 ing process employing a collector selected fromthe group consisting of aliphatic amines con taining a straightchainhydrocarbon group of at least 7 carbon atoms and their solublesalts formed by their combination with acids which are relatively devoidof surface active properties,

which resides in distributing in said pulp a useful amount of anauxiliary agent; consisting of dextrin, and thereafter subjecting thepulp to a separation treatment to remove the desired sylvite.

2. A method as set forth in claim 1, wherein the pulp is formedfromsylvinite ore and a substantially saturated aqueous solution ofthesoluble ore constituents.

3. A method as set forth in claim 1, wherein the sylvinite ore issubstantially deslimed before the collector and the auxiliary agent areadded.

' 4. A method as set forth in claim 1, wherein the separation treatmentis a froth-flotation treatment in a froth-flotation machine.

5. A method as set forth in claim 1, wherein the separation treatment isan agglomeration tabling treatment.

6. A method as set forth in claim 1, wherein a frothing agent is used inconjunction with the collector and auxiliary agent and the separation ofthe sylvite is effected by froth-flotation.

'l. A method as set forth in claim 1, wherein a petroleum oil is used inconjunction with the collector andauxiliary agent, the sylvite aglomerated and the agglomerates separated.

8. A method as set forth in claim 1, wherein the auxiliary agent is comdextrin.

9. A method as set forthin claim 1, wherein the auxiliary agent ispotato dextrin.

10. A method as set forth in claim 1, wherein octadecylamine acetate isused as the collector.

11. A method as set forth in claim 1, wherein n-heptylainlne acetate isused as the collector.

12. A method as set forth in claim 1, wherein laurylamine hydrochlorideis used as the collector.

13. A method as set forth in claim 1, wherein octadecylamine acetate isused as the collector in conjunction'with a frothing agent andseparation is effected by froth-flotation to remove the sylvite.

14. A method as set forth in claim 1. wherein octadecylamine acetate isused as the collector in conjunction with a petroleum oil andseparationds effected by agglomeration tabling treat- .ment to removethe sylvite.

